Bladder flap hematoma

Bladder flap hematoma is a hematoma between the uterus and posterior wall of bladder. They may be small (more commonly) or large (>5 cm, less common).

Clinical presentation

Small hematomas may be asymptomatic. Large ones may present with lower abdominal pain, dysuria, anemia and fever (if infected).

Pathology

It is an uncommon complication of cesarean section, due to bleeding and uterine dehiscence, usually at transverse lower uterine incision. It has also been reported with longitudinal incisions.

Radiographic features

Ultrasound

It is seen as heterogeneous solid lesion with variable amount of fluid component. Presence of gas foci strongly suggests infected hematoma or an abscess. It is less useful in demonstrating the dehiscence.

CT

May show slightly hyperattenuating fluid density in between posterior wall of bladder and uterus, however, MRI is preferred over CT.

MRI

It has the ability to distinguish the blood products (see: aging blood on MRI) and abscess. Sagittal and axial images have been very useful in demonstrating transverse lower uterine and longitudinal incisional dehiscence respectively.